Short version: it works, could be easier to install.Overall very useful and capable!!!
Long version: I moved a lot of files to Google Cloud Storage to use as a CDN for delivery of various assets and static images - it was cumbersome and time consuming to download/edit/upload them through the Console and I tried to get a utility which would help me do this - and mount a Google Storage Bucket as a drive in Mac OS X or Windows.
First I tried Mountain Duck (https://mountainduck.io/ - $49) which looks clean but unfortunately I would get spinning beach balls frequently and the 15 minute trial window just to short to really assess usefulness. Too bad cause I really liked the UI.
I then switched to Expandrive (https://www.expandrive.com/ - $49) which is the other tool that seems to support mounting a Google storage bucket as a drive. It's been good.
Installing was relatively easy, I added my project and used SSO to log in and give permission. I did have to grant permission for the extension to load in security - that could be improved if possible - but after that it's been smooth sailing.
I can mount all my buckets in the Finder and access my files that way - upload/download/delete etc... through regular move operations.
I can even open the files with my favourite editor and when I save them - Voila! They're instantly saved online. Overall it's a great solid product.
It also works for uploading backups to my coldine (=Google's version of Amazon Glacier) bucket to safeguard assets! Careful if you do this not to delete files and incur early deletion fees....
Other cloud storage access tools (e.g. Transmit Disk & CloudMounter) exist (for AWS for example) but they don't offer Google Cloud Storage support (many do Google Drive but it's another mechanism of course!)